With such vehicles, when the front wheels are pivoted relative to the front section in order to steer the vehicle, the actual steering angle will be modified by the angle of articulation between the front and rear sections of the vehicle.
When driving vehicles of this type, it is necessary to measure the actual steering angle, that is the angle of the front wheels relative to the rear section of the vehicle, in order to control the speeds of the rear driven wheels of the vehicle and provide differential control of the rear wheels when cornering. It is also necessary to let the operator of the vehicle know the direction in which the front wheels are positioned, when starting the vehicle from rest.
Hitherto, this has been achieved by means of separate sensors which measure the angle of articulation and the angle of the front wheels relative to the front section, and calculating from the two measurements, the actual steering angle. This requires some processing power.